The present invention generally relates to a system and method for automatically forming foam parts from a base sheet of material.
Foam inserts or cushions are commonly used to protect packaged goods. For example, a laptop computer or other consumer device can be packaged in a cardboard box for protection during storing, delivery, and the like. The box chosen for packaging the device typically defines an interior space that is larger than the dimensions of the device. In some cases, the extra space can be filled with foam peanuts, air filled bags, or other cushioning materials that can be arranged according to the dimensions of the box and the space that results around the packaged device in the box. However, in other cases, the device requires the use of foam inserts or cushions that can support the device in a particular position in the box, prevent movement of the device in the box, and/or provide particular cushioning characteristics. For example, a laptop computer is commonly packaged using foam inserts such as end caps. The end caps can be specially designed to correspond to the shape of the device so that the end caps can be fitted on the opposite ends of the device. In this way, the device can be supported or braced in the box and protected. In the example of the laptop computer, each end cap can define an inner surface that defines a cavity for receiving one of the opposite ends of the computer. The inner surface of the end cap is designed to correspond to the shape of the computer, and the outer surface of the end cap is designed to correspond to the shape of the box. Thus, when the computer is fitted between the end caps in the box, the end caps can support the computer in a particular position and prevent movement of the computer within the box. Any shocks to the box are transmitted to the computer by way of the end caps, which provide a cushioning effect to dampen the shocks and protect the computer. A variety of end caps and other foam inserts are known and commonly used in such applications.
Foam inserts often require a complex, three-dimensional shape in order to properly correspond to the products being packaged. These shapes are typically achieved by cutting polyethylene foam sheets to form different shapes of foam pieces that are then reoriented in a stacked configuration to build up the desired three-dimensional shape. While the foam sheets can be cut by machine, the assembly of the foam pieces is conventionally performed manually. In other words, a worker organizes the cut pieces of foam by hand, then joins the pieces, typically using an adhesive or heat, e.g., by heating the contacting surfaces with a hair dryer and pressing the pieces together by hand. This manual process, which is typically relatively disorganized and requires multiple successive operations for organizing and assembling the cut pieces, is labor intensive and limited in speed and quality by the speed and ability of the worker.
Foam inserts can also be manufactured using an automated method, such as is described in U.S. Patent Application Publication No. 2006/0127648, in which the insert is formed by stacking a plurality of sheets. In that case, the thickness of the insert is determined by the number of stacked sheets, and thick inserts generally require the use of much foam. For example, if one-inch thick foam is to be used to form an insert with a thickness of six inches, six layers of the foam are stacked. In addition, the cutting of holes in the various sheets results in wasted scrap material.
Thus, there exists a continued need for improved methods and machines for forming parts, such as end caps and other foam inserts. The method should be capable of being automated and capable of being used to form multiple inserts at a time. Further, the method should reduce the amount of material used and/or the amount of scrap produced.